Pic 400: Beware of Infection creeping down from left and right corners of ceiling. Do not let it attach to dooms on left and right sides as will prevent you from viewing the ceiling. With luck, 3 Holes in Ceiling potion might remove one of Infection bubbles. Charm/Wish of Antidote may come in handy here. Work the sides to drop diagonal rows of doom/black bubbles, then angle shots to drop center clusters of shadow bubbles. Rainbow useful here to prevent loss of cauldron bubbles. Once you drop sides and center clusters, the ceiling comes into view. Work your way up and drop the ceiling.